Grounding my van electrical.

Short_Shot

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The equipment ground serves 2 functions, maybe more.
1 Keep the system at the same potential as the planet its attached to.
That usually doesn't take a thick wire.

2 Clear a ground fault(allow the over-current protection to trip).
Wire should be big enough to clear the fault without the insulation melting.
This will probably require a thicker wire.
12 volt systems don't typically experience number 2 because there's no such thing as a ground fault when "ground" is exactly the same potential as the negative lead.

If you're grounding a higher voltage AC system to the chassis, that's a whole different ball game which is subject to its own particulars in order to ensure things such as GFCI and circuit baskets function properly.
 

DerpsyDoodler

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I havent seen any evidence of someone confusing ground with DC negative. Seems to me you're the only one causing confusion. DC negative will only reliably be at same potential of chassis if it is bonded (otherwise known as grounded) to the chassis.
 

Short_Shot

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I havent seen any evidence of someone confusing ground with DC negative. Seems to me you're the only one causing confusion. DC negative will only reliably be at same potential of chassis if it is bonded (otherwise known as grounded) to the chassis.
Which a van absolutely will be.

Bonding and grounding are also not the same thing at all, however mobile applications refer to it as such.
 

Short_Shot

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Also the confusion I referenced was the posts talking about "grounding" the case of a device and what size wire to use. The followup poster stated to use the same size "ground" as the positive after referencing the smaller "ground" then stating "however" etc.
 

rmaddy

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Also the confusion I referenced was the posts talking about "grounding" the case of a device and what size wire to use. The followup poster stated to use the same size "ground" as the positive after referencing the smaller "ground" then stating "however" etc.
You should actually quote the statements that you believe are confusing and point out the problematic statements and explain the issue. If done constructively, no one should be insulted. We all want to learn.

The whole point of this thread is asking about grounding device cases and knowing what size wires should be used.
 

Short_Shot

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You should actually quote the statements that you believe are confusing and point out the problematic statements and explain the issue. If done constructively, no one should be insulted. We all want to learn.

The whole point of this thread is asking about grounding device cases and knowing what size wires should be used.
OP definitely started the thread asking about positive and negative bus bars. Not grounding device cases.

These are two very different subjects.

Everything in his van will be at the same potential and thus is not in any way "grounded" nor is it necessary to do so with the vast majority of 12 volt components installed in a 12 volt vehicle lol
 

DerpsyDoodler

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Which a van absolutely will be.

Bonding and grounding are also not the same thing at all, however mobile applications refer to it as such.
omfg. Bonding and grounding are not the same thing and I didn't say they were. You said that. If you bond a cable from a bus bar to an acceptable ground, you have effectively grounded that bus bar. But sure, keep causing more confusion.
 

rmaddy

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OP definitely started the thread asking about positive and negative bus bars. Not grounding device cases.

These are two very different subjects.

Hmmm. You seem to be reading a very different question than I am. The OP starts off by stating (not questioning):
The electrical components of my system are run to positive and negative bus bars.

Then the OP asked:
Question: Can I ground the whole system by running a grounding wire from my negative bus bar to a chassis ground? If I do this, do I need to still run separate grounding wires from my solar charge controller, battery converter, and my inverter, or will the bus bar ground cover everything that is wired to them?

That is definitely asking about grounding, over and above the pos and neg wires already going to the bus bars.
 

Short_Shot

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While specifically still speaking about "grounding" the negative bar thus mixing up the two terms.


Because 12v negative is not ground. Nor is it a ground even when bonding the case to the same potential. Because it's the same potential.

That's what my entire rant was solely about.

On the off chance OP is running AC power, in that case it would be a ground in the technical sense and would be necessary to allow ground fault protection to function.
 

Short_Shot

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bonded (otherwise known as grounded)
You didn't say that huh

Yes I understand your context that it's "bonded" to a ground.

But it's still not a ground, being the whole pedantic point of my rant.

But you (both) chose to stop at the first line of my post.

The reason why the distinction matters is because I have, more than once, seen people attempt to improperly tie (bond) their neutral wires of their AC system to "ground" because of this constant insisting everyone does that 12v negative = ground, which itself is usually equated to "earth" ground.

It isn't a ground and anyone who has to ask these questions needs to understand that before they read the manual on a 120 or 240 vac product and install it on a "ground (earth) bonded neutral".

I'm ethically opposed to using the term in the 12v automotive industry, and anything remotely related to it, because I've seen people screw it up more than once, and I've been on the receiving end of some nasty shocks for it before I learned to use my brain and test it with a meter.


Now. Op didn't do anything of the sort that I'm aware of. Not even assuming they have plans to do so.

But it's clear that "negative" and "ground" have been equated.
 
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rmaddy

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While specifically still speaking about "grounding" the negative bar thus mixing up the two terms.

Because 12v negative is not ground.
No one but you has brought up the idea that 12V negative is grounding. The OP never stated it and none of the replies stated it.

The OP already has pos and neg wires going to pos and neg bus bars. All good. No grounding yet.

Now the OP is asking how to add proper grounding to the system, in addition to the existing pos and neg wires and bus bars. This is a valid, separate question.

The solution I employed (I have 24V), based on things I learned here and elsewhere, is to run the ground wires from the grounding screws on various device cases such as the inverter and SCC to the neg bus bar (this is in addition to the existing pos and neg DC wires for those devices). With all of the ground wires (and coincidentally the neg wires) connected to the neg bus bar, a ground wire can be run from the neg bus bar to the chassis.

Again, these extra ground wires are separate from the neg DC wires. No one is confusing the two in this thread.
 

Short_Shot

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No one but you has brought up the idea that 12V negative is grounding. ...*snip*... No one is confusing the two in this thread.
It was literally the very first thing you said. Telling OP to "ground" each device to the negative bus bar and then "ground" the bus bar.
Screenshot_20210803-104053_Chrome.jpg

If you're "grounding" the device to the bus bar you could just as well "ground" it directly to the terminal on the device and achieve the same effect.

It sounds like you're advocating running, for example, two let's say 0 awg wires from a device in addition to its 0 awg positive? That's nonsensical amounts of overkill lol

Regarding reading the manual, I stated that too. But that can never be repeated enough.


My point is still that none of it should be considered a ground in the context given the matching potential and thus complete inability to operate a ground fault device.
 
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rmaddy

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It was literally the very first thing you said. Telling OP to "ground" each device to the negative bus bar and then "ground" the bus bar.
View attachment 58626

If you're "grounding" the device to the bus bar you could just as well "ground" it directly to the terminal on the device and achieve the same effect.

It sounds like you're advocating running, for example, two let's say 0 awg wires from a device in addition to its 0 awg positive? That's nonsensical amounts of overkill lol

Regarding reading the manual, I stated that too. But that can never be repeated enough.


My point is still that none of it should be considered a ground in the context given the matching potential and thus complete inability to operate a ground fault device.
Yes, that's what I said. It's how every diagram from Victron shows it being done. It's how many people on this forum show how it's done.

One thing you haven't done is explain how you believe it should be done. It's doesn't help to state we are wrong but with no explanation of why it's wrong and how it should be done. Please show us the correct way.
 

DerpsyDoodler

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I am usually pretty self aware.

The distinction is incredibly important to be understood by any DIY installer who ventures off into the land of AC power.
I agree, the distinction is important to realize that just because youve bonded a wire to a terminal bar, or another wire does not mean you've grounded anything. If i say I bonded a device to ground, then I have grounded that device.

And now that chaos has effectively been stirred up, I wonder if I will get an answer to my question.
 

navillus

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Is this thread confusing dc negative with ground and using them interchangeably?

That's kind of inappropriate to do so and it has always driven me nuts that the industry has adopted the term "ground".

DC mobile equipment with a 12 volt vehicle and 12 volt components don't need a "ground" because the negative (which people are calling "ground") is itself at the same potential as the chassis.

My victron stuff for example is all 12v and has no enclosure ground of any sort. It does however have a 12vdc negative connection and this can be ran to a bus bar or any point on a 12vdc negative chassis.

Many times the chassis "ground" is rather poor but suitable upgrades can be done to provide a long lasting, electrically high quality negative path to your alternator and battery or batteries. I for example regularly run 90 amps through my truck chassis with minimal voltage drop, and what drop I do experience is from exceeding my alternator capacity.

If your connection from chassis to battery/alternator is good, then you can "ground" (not actually a ground but rather your 12vdc negative) can be done anywhere that is convenient as long as the connection point is free of paying and corrosion.


Some people will argue about galvanic corrosion but a car, van, or truck is not a boat.

That said:

If you CAN conveniently run everything to a single bus bar please do so. It makes life a lot simpler to have one really good chassis connection to this bar, plus a good lead to your batteries.

You always need a negative connection to your mobile equipment. You do not always need a "ground" because usually that's the exact same, electrically, as your negative lead as long as your vehicle voltage matches your power system voltage.

A 12 volt van with a 12 volt solar system means your negative and "ground" are exactly the same thing.


At the end of the day however, read the manual. Some devices may feature a small chassis ground in addition to a large negative cable even if the two leads are the same potential voltage.
20210802_145629_HDR.jpg

I have entire system grounded to chassis from her bus, with 4/0 cable. Inverter, mppt, power converter grounded with 10 awg, which is either manufacturer's spec or exceeding.
 

Short_Shot

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Yes, that's what I said. It's how every diagram from Victron shows it being done. It's how many people on this forum show how it's done.

One thing you haven't done is explain how you believe it should be done. It's doesn't help to state we are wrong but with no explanation of why it's wrong and how it should be done. Please show us the correct way.
First I'll address your requests for me to "explain how it's done".

I'm not saying you're doing anything "wrong" first of all. I'm only arguing against the term "ground" in the context here and that I disagree with the entire industry doing so as well.

Regarding your method however, since you keep insisting:

The manuals that suggest "grounding" don't show anything like what you're suggesting for this random epever model I just downloaded. I don't know what OP is using to get more specific.

It simply shows a negative wire to a not pictured (but we can just imagine) bus which is then itself "grounded". It then mentions "grounding" the case without any information on how or what size wire to use, just that it should be attached somehow.

Here's a screenshot from a victron system example off their website. It also shows no such oversized redundant ground wires installed alongside and equal in size to the negative from these devices.

Screenshot_20210803-111132_Drive.jpg

My two victron devices that I own both make no mention of doing so either. In fact there isn't even any provision on either one of them to ground the case as the mounting flanges are anodized and thus poor connectivity would be had, and the only screws anywhere on it are miniscule or in locations that would be difficult to get even a small ring terminal on.

I'm fact there is no mention of "grounding" any of it in my DC-DC charger manual.

1628007495687243707918100686300.jpg

But that's not what I care about lol. Overkill your "grounds" all it want.


It's this usage of the term "ground" I am protesting, not necessarily the wiring. Not sure why you keep asking that.

I didn't say anything should necessarily be done differently. I simply stated your suggestion to double up on the huge negative wire is overkill.

Do it if you want. It's electrically identical to simply not running anything extra at all and just putting a small wire from the case to the chassis. Overkill is fine if you have money to burn on wiring.

I'm only suggesting it should not be called a ground unless it's either earthed or specifically used at a different potential to allow ground fault protection to work, which would be the case for an AC install so long as the neutral isn't bonded to the chassis, which would be rather unsafe.
 

Short_Shot

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View attachment 58630

I have entire system grounded to chassis from her bus, with 4/0 cable. Inverter, mppt, power converter grounded with 10 awg, which is either manufacturer's spec or exceeding.
You're good homie.

I'm simply debating the usage of the word ground as it can lead to some very unsafe situations with enthusiastic DIYers in certain scenerios is all.
 

DerpsyDoodler

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So continuing on the topic of grounding:

Given a choice between having a gfdi on the negative bus vs having the negative bus grounded in the traditional manner (with a low resistance connection directly to ground), which offers more/better protection?
 
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